Power semiconductor devices used for power control are required to have low power loss during operation. Specifically, it is important to reduce the on-resistance in switching control. This requires a technique for reducing the internal resistance resulting from the device structure and the contact resistance between the metal electrode and the semiconductor.
Silicon carbide (SiC) is a wide gap semiconductor having a wide forbidden gap and hence is more resistant to high electric field than silicon. This enables reduction of the internal resistance. Thus, SiC is promising as a material for realizing a power semiconductor device with lower power loss. However, because SiC is a wide gap semiconductor, it is difficult to reduce the contact resistance between SiC and the metal electrode. Techniques for solving this problem are currently under study.